Organolanthanide chemistry

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Organolanthanide chemistry is the field of chemistry that studies compounds with a lanthanide-to-carbon bond.

Background

With the exception of lutetium, all lanthanides belong to the f block. At room temperature, they are shiny metals that usually corrode easily (europium, for example, corrodes in air to form an oxide within seconds.) Most of them tend to be powerful reducing agents and can readily reduce transition metal compounds to the pure metals. Lanthanum, for instance, has a reactivity comparable to magnesium with a reduction potential of -2.37 V for the reaction:

  • La3+ + 3e- → La

Organolanthanide compounds are different from their d-block cousins in the following ways:

  • They are far more air- and water-sensitive and are often pyrophoric.
  • Chemistry in the 0 oxidation state is far more limited. In fact, their electropositive nature makes their organometallic compounds more likely to be ionic.
  • They form no stable carbonyls at room temperature; organolanthanide carbonyl compounds have been observed only in argon matrices, and decompose when heated to 40 K.

Alkyl reactions

Metal-carbon σ bonds are found in alkyls of the lanthanide elements such as [LnMe63- and Ln[CH(SiMe3)3. Methyllithium dissolved in THF reacts in stoichiometric ratio with LnCl3 (Ln = Y, La) to yield Ln(CH3)3 probably contaminated with LiCl.

If a chelating agent (L-L), such as tetramethylethylenediamine (tmed or tmeda) or 1,2-dimethoxyethane (dme) is mixed with MCl3 and CH3Li in THF, this forms [Li(tmed)]3[M(CH3)6 and [Li(dme)]3[M(CH3)6.

Aryls

Certain powdered lanthanides react with diphenylmercury in THF to yield octahedral complexes:

  • 2Ln + 3Ph2Hg + 6THF → 2LnPh3(THF)3 + Hg (Ln = Ho, Er, Tm, Lu).
CH He
CLi CBe CB CC CN CO CF Ne
CNa CMg CAl CSi CP CS CCl CAr
CK CCa CSc CTi CV CCr CMn CFe CCo CNi CCu CZn CGa CGe CAs CSe CBr CKr
CRb CSr CY CZr CNb CMo CTc CRu CRh CPd CAg CCd CIn CSn CSb CTe CI CXe
CCs CBa CHf CTa CW CRe COs CIr CPt CAu CHg CTl CPb CBi CPo CAt Rn
Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Fl Uup Lv Uus Uuo
↓
CLa CCe CPr CNd Pm CSm CEu CGd CTb CDy CHo CEr CTm CYb CLu
Ac CTh CPa CU CNp CPu CAm CCm CBk Cf CEs Fm Md No Lr
Chemical bonds to carbon
Core organic chemistry Many uses in chemistry
Academic research, but no widespread use Bond unknown